Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

614
FXUS63 KLOT 160009
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
609 PM CST Thu Jan 15 2026

.KEY MESSAGES...

- Accumulating snow is expected tonight, likely resulting in
  hazardous travel conditions.

- Isolated to scattered gusty snow showers late Friday afternoon
  into early evening may produce locally slippery travel for
  the evening commute.

- Several clipper-like systems within northwest flow aloft will
  bring periods of snow showers and renewed bouts of very cold
  and windy conditions. Bitterly cold conditions are expected
  Sunday night through early Tuesday.

&&

.DISCUSSION...
Issued at 250 PM CST Thu Jan 15 2026

Through Early Friday Afternoon:

Afternoon water vapor imagery depicts a shortwave impulse
working across Minnesota en route to Wisconsin. Regional radar
imagery shows a few pockets of snow showers on the leading edge
of this wave working into northwestern portions of WI. Ahead of
the snow showers is a plume of snow aloft that doesn`t appear to
be making it to the ground owing to dry low level air preceding
the wave. The system will work across north-central WI tonight
and drag its cold front across the CWA providing our next
opportunity for accumulating snow. Isentropic ascent will kick
off late this afternoon in the low level warm advection wing in
advance of this wave. However, with the low levels being so dry,
there won`t be much moisture to loft initially and we too may
end up with a few hour period of virga snow showers or possibly
a few flurries. The snow shower potential will really pick up
during the mid-late evening period while the low levels quickly
moisten up. From there, we expect a few hour period over any
given location of light accumulating snow into the overnight.
This should lead to reductions in visibility, possibly down to
or even below one mile from time to time, and slippery road
conditions.

Model guidance likes the idea of a few hour lull in activity
ahead of the storm`s cold front in which we may end up dry or
with only lingering flurries late overnight into very early
Friday. The front will approach our western CWA during the
predawn hours and a second push of accumulating light snow is
anticipated along and immediately ahead of the boundary. The
time window for this second push would be predawn in our west
through about mid-morning to exit to our east. This will
reinforce the visibility and slippery travel concerns for the
morning commute. While this doesn`t appear to be an overly
impactful event, at the least expect a slower-moving commute
tomorrow. By the end of tomorrow morning, widespread
accumulations around or just over an inch are forecast with 2"
being on the higher end of expectations. After the trough axis
shoves the main body of precip to our east, the late morning
through early afternoon period could feature scattered flurries
around the area.

There is a weak signal among some camps for us to lose out on
cloud ice during a few hour window overnight and again during
the morning. Forecast soundings from the GFS and NAM are most
bullish on this potential, but even then the signal is very
marginal and neither model resolves any freezing precip
outright. Latest RAP and HRRR soundings depict a deeper
saturated layer through the night which would favor all snow. If
anything, the signal is slightly stronger tomorrow during the
late morning and early afternoon, but this would come after the
system precip and in the form of only a brief period of light
freezing drizzle, if at all. Plus, temperatures should be
pushing above freezing right around this time which should
further limit any potential impacts. Expectations for now are
for precip to remain in the form of snow with no formal mention
of freezing rain/drizzle in the forecast, but will keep a close
eye on observations as the system moves across.

The cold air will really begin to fill in aloft during the
afternoon. This will steepen up low level lapse rates as a
secondary trough axis and vort lobe are progged to swing across
the CWA. This will provide yet another chance for accumulating
snow, possibly heavier at times. More details on this
afternoon/evening potential can be found in the long term
discussion below.

In other news, the warm advection later today will keep
temperatures rather steady in the lower and middle 20s from now
through most of the overnight. The stronger warm advection just
in advance of the cold front will drive temperatures up a few
degrees prior to daybreak and we should wake up to middle and
upper 20s. We`re looking at middle and upper 30s for the
afternoon. Gusts will also begin to pick up overnight with the
initial push of snow and stay up through the day on Friday.
Southwest to west winds will gust to between 25 and 30 mph, with
the strongest winds expected overnight and Friday afternoon.

Doom


Late Friday Afternoon through Thursday:

Stout ridging currently developing over the eastern Pacific
toward the Gulf of Alaska will dislodge a series of arctic
disturbances SSE toward the Great Lakes region this weekend
through early next week. Bitterly cold conditions are expected,
especially Sunday night into Tuesday. Each shot of colder air as
well as persistent cyclonic flow aloft will support periodic
snow showers and flurries during this time.

The first arctic front will sweep across the area late Friday
afternoon into mid-evening. Low-level moisture profiles appear
marginal for snow showers with the front, but a modestly deep
layer (up to 10kft) of steep low-level lapse rates combined with
temps quickly falling through the 20s and WNW winds gusting to
30 mph or higher does raise concern for localized snow squall
conditions roughly in the 4-8pm window. Given that this aligns
with the peak Friday evening commute time, it would not take
long for impacts to quickly mount. Still feel moisture
availability will be the limiting factor for genuine robust
squalls, though upstream trends across Iowa earlier in the
afternoon should provide some lead time if coverage and/or
intensity is higher than currently expected.

Another pair of trough axes will bring a renewed chance of snow
showers Saturday evening and again Sunday afternoon into the
evening. Inversion heights lowering to under 6kft will limit
intensity, but with the cloud layer residing mostly in the DGZ
for both periods, even meager moisture will result in at least
some lighter snow showers.

Expect daytime highs this weekend to settle in the mid to upper
teens amid gusty WNW to WSW winds, resulting in wind chills
topping out only just above zero. A next push of arctic air will
arrive late Sunday afternoon and evening, with notably colder
conditions Sunday night into Tuesday. Minimum wind chills Monday
morning are expected to be around -20 degrees, with the
potential that a Cold Weather Advisory (-25 degrees) is needed
for at least some of the area. With the cold start to the day,
highs Monday may struggle to reach 10 degrees, with maximum wind
chills remaining solidly below zero. Winds will begin to
diminish Monday night as a surface high passes south of the
area, but wind chills as low as -15 degrees can be expected
Tuesday morning.

Beyond Tuesday, strong baroclinicity developing across the
central CONUS will support a more active period of weather near
or south of the area. Still a lot of discrepancies in the
broader model/ensemble systems chiefly due to uncertainty as to
where the baroclinic zone resides with respect to out area.

Kluber

&&

.AVIATION /00Z TAFS THROUGH 06Z SATURDAY/...
Issued at 609 PM CST Thu Jan 15 2026

Key Messages:

- Two periods of steady snowfall are expected tonight, each
  likely with IFR visibilities.

- Gusty snow showers will likely affect the terminals tomorrow
  afternoon/evening.

- MVFR ceilings are expected to be prevalent through much of
  the TAF period.


Multiple rounds of snow are expected during the 00Z TAF period
as a sprawling weather system traverses the Great Lakes. An
initial thump of snow is expected to arrive during the latter
half of this evening. While the steadier snowfall isn`t expected
to last for more than 3 hours, it will likely fall at a steady
enough clip to reduce visibilities to IFR levels for a time and
produce a quick coating of snow accumulation. Thereafter, a 3-4
hour lull in the steadier snowfall is expected, though it
remains possible that some flurries or poor quality snow showers
occur during this relative lull.

A second wave of steady snowfall will likely arrive at the
terminals closer to daybreak. Much like the first round of snow,
this follow-up round of snow will also likely last no more than
3-4 hours at any one location while also producing IFR
visibilities and another quick coating of accumulation. The
total snowfall accumulation between the two rounds of steadier
snowfall will likely end up being somewhere around one inch.

Another lull in the snowfall is expected from mid-morning
through the early afternoon tomorrow. However, scattered gusty
snow showers are likely to develop during the afternoon and
produce on-and-off visibility reductions through at least the
early evening tomorrow. Air temperatures warming into the mid
30s by this point should tend to limit any dustings to colder
and grassy surfaces, if that.

Ceilings are generally favored to stay in the MVFR flight
category from during and after the first round of snow through
much of the rest of the TAF period, though there is some chance
for IFR ceilings to be observed both during and just after the
steadiest snowfall. Winds will remain out of a southwesterly
direction through tomorrow morning, gusting in excess of 20 kts
on at least an occasional basis. They will then shift westerly
behind a cold front tomorrow afternoon, though similar (or
slightly higher) wind magnitudes are expected to be retained
behind the front.

Ogorek

&&

.HYDROLOGY...
Issued at 1209 PM CST Thu Jan 15 2026

The upcoming extended period of very cold temperatures will likely
result in the rapid development of ice on area rivers and streams
which may increase the chance of localized ice jam flooding. Last
week`s heavy rainfall has resulted in increased streamflow in
several basins, including the Fox, Des Plains, and Illinois River
basins. This higher streamflow will result in a greater potential
for freeze up ice jam flooding.

- Izzi

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 6 PM CST Friday for Winthrop Harbor
     IL to Gary IN.

     Small Craft Advisory until 6 PM CST Friday for Gary to Burns
     Harbor IN-Burns Harbor to Michigan City IN.

&&

$$

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